For example, JP-A-2009=196473 discloses one example of a conventional vehicular headup display device (HUD device). The vehicular HUD device is configured to modify a display position of a virtual image indicating information, according to a position of a driver's eyes. The vehicular HUD device includes an indicator and a combiner. The indicator includes a liquid crystal display device, a first reflector, a second reflector, and the like. The indicator is accommodated in a case and located in an instrument panel. The combiner is, for example, a half mirror layer having reflectivity and transmissivity to light. The combiner is formed in an inner surface of a windshield. The liquid-crystal-display device indicates an information image exhibiting information such as a traveling speed. The first reflector reflects light of the information image to the second reflector. The second reflector is a rotatable concave mirror configured to reflect the light reflected by the first reflector to the combiner. In this way, the information image is indicated as a virtual image at a predetermined display position: The second reflector is fixed to a shaft. The shaft is fixed to a bearing at one end to be rotatable. The shaft is fixed to a motor, such as a stepping motor, at the other end. The motor is configured to rotate the shaft in a clockwise direction or a counterclockwise direction by an angle, corresponding to an electric signal received from an external device such as a control device. In this way, the motor rotates the second reflector, thereby to modify the display position of the virtual image. As described above, the HUD device may employ a stepping motor as a motor to modify the display position of the virtual image. In this case, when the display position of the indicated virtual image is modified, movement of the virtual image may not be viewed smoothly. That is, movement of the virtual image may be viewed stepwise. Accordingly, an HUD device is required to enable movement of an indicated virtual image to be viewed smoothly when the display position of the indicated virtual image is modified.